Permsteading.com

Oh, I would use the larger one as the first one, the smaller barrel as the second. Look at Ray's thread "RMH in NH" for ideas on the wood floor.
viewtopic.php?f=6&t=368
Here's the core videos:

Thanks Again and Again Matt !!!
I was watching the core casting video when your reply notifications arrived - it is paused now - great work, thanks for making and sharing that - it is the very best presentation I've ever yet seen in over a year of looking around for good info !!!

Sorry for the drift.

I don't go to Donkey's board. I could but would rather not. It would be nice if there was a separate thread containing alternative mass/flow designs on this site.

A small opinion & perspective & compliment:
Maybe I am old & old fashioned & too altruistic, but IMO discussion boards are the best of the best WHEN they work properly.

By the above I mean that they are great at providing a conduit for people to willingly help other people if they will do so.

I only just found this board - was powerfully impressed by the friendly, helpful postings on it, and so I joined ASAP.

As soon as I was able to, I posted a variation of a thread already posted days ago someplace else which had gotten exactly zero replies at that other place - but here ?!?:

The site admin himself pitched right in, in the most helpful manner imaginable - and how cool is THAT !?!

There are discussion boards which seem to be just like closed fan clubs where a small group post to one another, and either ignore or outright shun any others who dare to try and join in. (Why leave membership open, I wonder ??)
Added to that are those places which insist upon having hard to read themes (mostly black, nasty for these old eyes !!).

Many areas of my own life have been improved by the help freely given by way of discussion boards and in fact, I have survived and I am healing from a deadly illness all because of help given freely to me in this manner; my car has been fixed when it needed a $300+ repair - for just $10 by way of the same type of conduit.

When one is desperately ill, a thing which can keep one from going insane is to work at learning new things; a good way to learn things is by reading and sharing with others.

So=> here we have the best of all worlds, a discussion board which is easy on the old eyes, peopled by friendly, helpful folks who are obviously very willing to help even total newbies like myself.

A great example of the best of the best of the best in my opinion and my compliments to all who help others freely !!!

I noticed you said the floor is 'old wood'.

What is under the old wood? Like Manny said, these things are heavy...his weighs 3.5 TONS. You'll want to make sure it doesn't end up in the basement. If you have a slab floor no problem. If not, you'll want to put some pipe jacks and crossbeams under there to take the weight.

Here is a design I've come up with recently, to look more like a regular fireplace insert. Perhaps a bit much for your situation, with that room off by itself, but this post may give you ideas/ options. I'd just build it where i wanted and run the exhaust pipe up through the roof wherever i built it, but I'm weird (so people keep insisting). If there is a second story try to run the exhaust up through a closet?



Below you can see how the stone facade around the fireplace will look. I'll surround the whole thing with a wood frame/ sheetrock wall, with access panels behind the flat panel TV and on the sides. Notice the ash clean-out trays on either side at the bottom of the 'bells'. Thermo-ceramic glass in the side of the feed chamber lets people see the fire. There will be a cavity up behind the mantlepiece above the feed chamber to permit loading longer wood. Just stick it up behind the stone face then lower it down into the feed chamber. Sheet steel plenum under the drum (around the bottom of the heat riser) funnels exhaust into the first concrete block/ brick 'bell' on the right. 8" duct funnels exhaust behind and across into the second 'bell' on the left, turning upwards at the end so the input is above the output pipe. My Tee for priming the system when it's cold will hide behind a thin swing-out rock in the facade.

Oddmar, that is a cool design. I have a couple questions. Is it safe to cover the brick bells with a wood frame/sheetrock wall? Would the wall hinder the performance of the brick bells?

Hello Oddmar and thanks.
This will not and may not weigh into the tonnage range - it is on a 2nd floor with a bedroom below it.

As Matt had illustrated in his contributions in this thread - what I'll make (like his, I hope) will be not as efficient as a 3.5 ton monster - but WAAAY better than an old, badly located single-pass box stove.

The heaviest bit will be a limited thermal battery, most likely just made from a pile of smallish rocks inside a barrel.

Since the room it is to go in is small and has 2-3 good load bearing walls beneath it, I am not too worried about this heading for the basement - and I do thank you for the reminder.

Maybe someday I will make a real, heavy, seriously efficient RMH; the present effort is all about improvement rather than perfection - which will just have to wait a while...

Best Wishes to All !!!

Devilsbrew, Yes, any insulating material which encases the mass will slow the transfer of heat, but i was planning to build a 2x2 stud wall an inch or so away from the mass to allow for airflow. My original build had wood in direct contact with the mass (8" system) with no safety problems, but I always prefer a little more fire safety.

Hagrid, here's a different design. I modified a drawing i'd done some time ago. Be aware the output from the drum should be on three sides of the burn tunnel so as not to constrict the flow, i just didn't draw it that way because it becomes too cluttered to easily comprehend.

If you were to cast a 5" riser with 2" thick walls, you could use a 14"-16" diameter 30-gallon drum instead of the pictured 50-gallon drum. A 5" riser has a CSA of 19.6", so your burn tunnel could be 4" square, 16 sq in. (A burn tunnel smaller than the CSA of the stove makes it more 'rockety'. The air just sucks through faster)

Note the Peterburg fresh air injection plate in the feed chamber, and the Peterburg 'tripwire' cast into the ceiling of the burn tunnel. The plate can be 1/8" thick metal, and there should be a 3/8" gap between it and the face of the feed chamber. It should curve slightly into the burn tunnel. The fast-moving air siphons in extra oxygen, improving the combustion efficiency. The tripwire (cast at an angle across the ceiling of the burn tunnel) makes the hot gases tumble, bringing more oxygen into contact with fuel particles. The majority of the combustion in the burn tunnel takes place along the ceiling, where it's hottest.

I really like both of those Oddmar. I hope we get to see the fireplace build in action, I think it's a great concept.

I don't have much to add to this discussion Small, the other guys know a lot more about Rocket Stoves than I, But I would like to say Welcome, nice to have you with us.